Contour reproducing apparatus



July 14, 1942. H. THRAsHER 2,289,532

CONTOUR RElRODUCINGrv APPARATUS Filed July 5, 1940 sheets-snee; 1

July 14 1942. H. THRASHER CONTOUR REPRODUCINGVAPPARTUS Filed July 5,1940 2 Sheets-Sheet 2 qyw `Patented July 14, 19.427 l UNITED STATESPATENTfor-Flcn CONTOURREPRODUCING APPARATUS Howard Thrasher, Long Beach,Calif.,'alsinor to Vultee Aircraft, Inc., Downey, Calif., a oorporationof Delaware Application my s, 1940, seran No. 343.916

(ci. ss-'zn 7 Claims.

'The present invention relates generally to apparatus for reproducing onplates or other surfaces the contours of templates. More particularlythe invention relates to that type of contour reproducing apparatuswhich operates on the pantograph principle and comprises (l) a base withen upstanding pivot pin thereon, (2) a pair l of long centrallycrossedprimary arms having the 'central portions thereof mounted on, androtatable relatively to, the pivot pin, (3) a pair of short tracing armsextending between the ends of the primaryarms that are at one side ofthe base andhaving the outer ends thereof pivotally connected to suchends of the primary arms and their Ainner ends pivotally connectedtogetherl and `provided with means for supporting a tracing tool, and(4) a pair of short scribing arms lextendingbetween the other endsl ofthe primary 4 arms, i. e.,the ends at the other side of the base.

and havingA their outer ends pivotally connected to the lastmentionedends of the primary arms and their inner ends pivotallyvconnectedtogether and provided with means for retaining a scribing tool.

One object of the invention is to provide a `contour reproducingapparatus of this type which has greater capabilities of use thanpreviously designed apparatusfor the same purpose and is of such designand construction that it is extremely accurate and may be operatedlexpeditiously.

. Another-objectV of the invention is to provide a I proved design and acaster for 'supporting the inner ends of the scribing arms.

A still further object of the invention is to provide a contourreproducing apparatus which is generally of new and improved design andnot only may be produced at a low and reasonable cost but also isespecially designed and adapted for use in connection with aircraftwork.

Other objects of the invention and the various advantages andcharacteristics of the present contour reproducing apparatus will beapparent from a consideration of the following detailed description.

The invention consists in the several novel features which arehereinafter set forth and are more particularly defined by claims -atthe conclusion hereof.

In the drawings which accompany and form a 'l part of this specificationor disclosure and in contour reproducing apparatus of the typeunderconsideration in which the centrally crossed primary arms are formed oftubes and embody a truss design or arrangement whereby they are so rigidthat they are free from bending or deflection during use of theapparatus.

which like numerals of reference denote vcorresponding parts throughoutthe several views:

' Figure 1 isa plan view of a contour reproducing apparatus embodyingthe invention;

Figure 2 is a vertical transverse section taken on the line 2--2 ofFigure 1 and showingin detail the 'design of the supporting base and theconstruction and arrangement of the centrally l Another object of theinvention is the provision 4 in connection with a contourreproducingappa* ratus of the type yand character under consideration of a simpleand novel attachment'which is adapted to be used in connection with thetracing tool and makes it possible to produce an unldersized contour.

Still another object of the vinvention is the provision of an attachmentwhich is adapted for connection to the tracing tool and enables the userof theapparatus to produce an oversized contour.

-A further object of the invention is to provide a contour reproducingapparatus having novel forms or types of pivotal connections between theinner ends ofthe short tracing and scribing arms and in addition asupporting base of im-l Figure 5 is a side view or elevation of theplvoted inner ends of the tracing arms', illus- .trating in detail thedesign and construction of 'the tracing tool and showing the latter withthe attachment for use in connection with the reproduction of oversizedcontours;v

Figure 6 is a horizontal `section taken on the line 6--8 of Figure 5;and

Figure 7 is an enlarged vertical sectional view 'showing the pivotalconnection between the `inner ends of the scribing arms and illustratingin detail the construction and` design of the v scribing tool and thecaster for supporting the scribing arms. ,i

The apparatus which is shown in thev drawings constitutes the preferredembodiment of the invention. It is designed and adapted to reproduce ona plate P the contour of a template T and comprises a supporting base8.a a pair of primary arms 8 and I8, a pair of tracing arms II and apair of scribing arms I2. It 'is contemplated that the plate P and thetemplate T be placed in side by side relation on top of a table or othersuitable horizontal supporting surface. When the apparatus is used, ashereinbefore pointed out. it serves to scribe on the top face of theplate P the contour or outline of the prises a hub forming sleeve 20. apair of short tubes 2I, a pair of long centrally bowed tubes 22 and apair of diagonal brace forming tubes 23. 'I'he sleeve 28 surrounds andis rotatable relatively to the sleeve I8 of the arm 8 and is heldagainst vertical displacement with respect to the latter. The shorttubes 2| are fixed to and radiate from the lower end of the sleeve 20and are positioned one diagonally opposite the other. 'I'he long tubes22 of the arm I0 are disposed in opposed relation an dextendhorizontally. 'I'he central portions ofthe last mentioned tubes arewelded or otherwise flxedly secured to the outer ends of the tubes 2land the outer ends of the tubes 22 are welded together as shown inFigure l. The diagonal brace forming tubes 23 radiate from the sleeve 20and have the inner ends thereof flxedly secured to the upper end of \thesleeve. 'I'he outer ends of the tubes 23 are joined to the outer ends ofthe tubes 22 at the juncture points of such tubes. The sleeve 20 permitsthe arm I8 to rotate in a horizontal piane are provided with knurledheads I8 so that they may be readily turned in connection withadjustment thereof. Turning of the legs in one direction operates toraise the supporting base and turning of the legs in the opposite orreverse direction results in lowering of the supporting base.

The legs have longitudinally extending holes in their central portionsin order to accommodate nails in the event that the user desires to nailthe apparatusto the floor. The pivot pin I4 is ilxedly secured to thecentral portion of the supporting base 8, as shown in Figure 2, andextends upwardly at right angles to the base. It is of uniform diameterfrom one end thereof to the other and serves. as hereinafter described.as the pivot medium for the central portions of the primary arms 8 andI8 of the apparatus.

The primary arms 8 and III are comparatively long, as shown in Figures 1and 2, and are centrally crossed. They are ,centralLv pivoted on thepivot pin Il in order that they are free to rotate in a horizontalplane. The two arms are equal in length. The arm 8 is of truss 'designand consists of a hub forming vertically extending sleeve I8, a pair ofshort ltubes SI1, a pair of long centrally bowed tubes I8 and apair ofdiagonal brace forming tubes Il. The hub forming sleeve I8 extendsaround and is rotatably mounted on the pivot pin I4 on the supportingbase 8 and together with the pin forms a central pivot whereby the arm 8is permitted to swing freely in a hori- -zontal plane either in aVclockwise or counterclockwise direction. The short tubes II radiatefrom the lower end of the sleeve I8 and are positioned one diametricallyopposite the other. The inner ends of the tubes I1 are welded orotherwise rigidly secured. to the lower end of the sleeve I8 and theouter ends are welded or otherwise secured tothe centrally bowedportions of the long tubes Il. Said long tubes, as shown in Figures 1and 2, extend horizontally. They are disposed in opposed relation andhave the outer ends fixedly secured together. The tubes I8 radiate fromthe sleeve Il and have the inner ends y thereof welded or otherwisesecured to the upper end of the sleeve. The outer ends of the primaryarm i8 is substantially the same in .design and construction as the arm8. It ccmeither clockwise or counterclockwise and also relatively to thearm 8. 'I'he tubes of which the two arms 9 and I0 are principally formedare preferably metallic tubes although tubes of other material may, ifdesired, be employed. By properly adjusting the screw type legs I3 ofthe base 8 the pivot pin I4 may be positioned perpendicular to the endthat the arms 8 and I0 rotate in a truly horizontal plane.

The tracing arms II extend between the ends of the primary arms that areat one side of the supporting base 8. They are preferably in the form ofmetallic tubes and are joined at the outer ends thereof to said ends ofthe primary arms by pivotal connections 24, as shown in Figure 1. I'heinner end of each tracing arm II is provided with a ring shaped member25. The two members 25 are positioned one above the other. They arecoaxially arranged and surround a vertically extending tubular holder 26for a tracing tool 21. Two ball bearings 28 extend between the ringshaped-members 28 and the central portion of the holder 26 and togetherwith the holder form a pivotal connection between the inner ends of thetracing arms I I. Said bearings are positioned one above the other andcomprise4 inner races 28, outer races 30 and balls 3| between the innerand outer races. The inner races surround the central portion of theholder 26 and are clamped against a shoulder 32 on the upper end of theholder by means of a nut 33 on the lower end of the holder. 'I'he outerraces 30 of the ball bearings 28 are pressed or otherwise nxedly securedwithin the inner peripheries of the ring shaped members 28. The tracingtool 2'I extends vertically through the tubular holder 28 and has asocket 34 in its lower end. The upper end of the holder 28 is externallythreaded 'and split longitudinally and has a nut 35. When this nut istightened it contacts the upper end of the holder around the tracingtool 21 and thus locks the tool against vertical displacement relativelyto the holder. The holder 28 serves to hold the tracing tool 21 so thatits center line coincides with the true center of the pivotal connectionwhich is formed between the inner ends of the Y tracing arms I I by theball bearings 28.

The scribing arms I2 extend between the ends of the primary arms thatare at the opposite side of the supporting base 8 and are preferably inthe form of metallic tubes. They are disposed and move in a horizontalplane and are the same in length as the tracing arms II. The outer lends21,289,582 oi' the scribing arms I2 .are joined bythe ad.

pivotai connection between the inner endsoi' thescribing arms I2. Theinner races of the ball lation with the edge of the template. When theattachment 44 is in place and the tracing tool 21 'tis moved so astocause the roller 40 to move around the edge of thetemplate thescribing tool 39 scribes or marks an undersized contour on the plate P.Because o! the manner in which the roller 4l is mounted the distancebetween the roller and tracing tool may be varied in order to v adjustor change the amount of undersize of the bearings are clamped against ashoulder 4I at the upper end of the holder by means of anut 42 on thelower end of. the holder. The scribing tool 39 tits slidably in theholder ll and has a pointed mounted on the upperend of the tool 8 9 andserve to urge the point oi' the tool into contact with the plate P. Byremoving or adding weights the tool may be properly weighted. Because ofthe design or arrangement and pivotal connection of the primary,tracing-and scribing aims the scribing tool 39 is caused during movementof the tracing tool 21 to move conformably or correspondingly to thetracing tool. When the pointed end of the scribing tool 39 is on the topfaceA of the plate P and the traping tool 2 1 is moved around the edgeor periphery of the template T vthe scribing tool marks or scribes onthe top surface oi the plate P the contour'of the template. If thetracing tool 21v is moved around the template T at a ilxed distanceinwardly of the edge of the template the contour which is formed by thescribing i001 as on the plate P will bec: sulv tachment 44 for use inundersiz'ed Acon-4v scribed contour. When the lever BI is moved ina'counterclockwise direction. as viewed in lIiigure 4. the'roller 4l andthe tracing tool are moved apart and this results in a contour oi' largeunder. size. When the lever 5I is swung in a clockwise direction, asviewed in Figure 4. the roller and tracing tool,are moved together withthe result lower end for scribing purposes. Weights are.

tours and a tracing tool attachment v for use in v making oversizedcontours. l The attachment 44 (see Figures 3 and 4) comprises a-plate 46'in the shape oi' a quadrant. an

of the plate 46 and a template-engaging roller l' -upstanding connectingpin 41` on the inner corner 48 lbeneath the plate. The pin 3 1 isadapted to fit snugly within the socket 34 at lthe lower end of thetracing tool 21 and serves when in place in the socket to connect theplate 46l of the attachment 44`fixed1y to the tracing tool. The roller4l is adaptedv toenage and travel along the edge of the template T, asshown in Figure. 4. It islocated under the central portion of the plateand it serves, as hereinafter described, to hold the scribing tool 21 apredetermined distance inward- 1y of the edge of the template. It ismounted roc `lever projects in the direction of the curved edge of theplate and substantially radially withrespect to the connecting pin 41.'I'he pivotal connection 52 is located at rthe center of the arcuateslot 50.. Because of the position of the roller 48 the roller serves to'hold the tracing tool 21-at av a predetermlned'distanceoutwardly of theedge ofthe template. When the roller is in contact that the amount ofundersize as far as the scribed contour is concerned is a minimum. Byadjusting the position oi the roller with respect to the tracing toolany desired amount of undersize may be obtained as far as the scribedcontour is concerned. The size of the slot |50 is such that when thelever 5I is swung clockwise to the fullest ex- 4tent the center line ofvthe tracing tool 21 is in alignment with the periphery of the roller48. When the tool 21 is positioned so that the center line thereof is inalignment with the periphery of the roller and the roller is movedaround the edge of the template the scribing tool 39 makes or scribes acontourwhich is exactly the samein size and shape as the template. Theouter end of the long arm of the bell crank lever 5I isin 1 the form ofa pointer andv this coacts with ascale 53 on the curved margin of theplate 46 to indicate the distance between the roller and the tracingtool 21; When it is desired to use the contour reproducing apparatuswithout the attachment 44 it is only necessary to raise the tracing tool21 or lower the attachment 44. Either operation results in disconnectionof the attachment from thetracing tool.

The attachment 45' for use; in making oversizedcont'ours comprises aconnecting pin. and a roller. T'he roller is rotatably-mounted on thev 4lower end of the pin. The pin is adapted to ilt within the socket. inthe lower end of the tracing tool 21 and serves to 4hold the attachment4 5 in connected relation with said tool 21. The

Vrouer is adapted to 'contact with the edge or the template T and servesto hold the tracing tool with the edge'of the template and the tracingtool is moved around the template the scribing tool 33 scribes anoversizedcontour on the plate P.

By substituting rollers of different diameter for .the rollers oftheattachment 45 the lattachment may be made to effect any desired amountoi oversize 'as far as the scribed contour is conleo cemed; When it isdesired to remove the attachment 45 it is only necessary to withdraw theconets 55 to the innerend of one o f the scribing predetermined distanceinwardly o! the. edge of arms I2. During a contour reproducing operationthe caster rolls over the top, face of the plate P and holds the holder38 at a fixed distance above the plate. 'Ihe caster, as shown in Figure7, comprises a roller 56 and a vertically extending d pivot pin 51. Thelower end of the pivot pin is the template Whenthe rollerls inContacting lebent at right angles and serves as a hub for the centralportion of thevroller. The upper end of the pivot pin extends throughaligned holes in the clamp brackets 55 in order that the caster M isfree to swivel or rotate about the axis of the pin. The clamp bracketshave bolts 5B for clampingthem together and embody any suitable meansfor preventing axial or vertical displacement of the pivot pinrelatively thereto.

The herein described contour reproducing apparatus is essentially aprecision instrument because of the truss arrangementv or design of theprimary arms 9 and I0. It may be manufactured at a comparatively low andreasonable cost and is characterized by the fact that the attachments 4Iand 45 enable the user to make either undersized or oversized contours.By reason of the two attachments the apparatus has particular utility inconnection with aircraft work where great precision and accuracy arecalled for. In the apparatus which is shown in the drawings the primaryarms are pivotaily connected at their centers and are twice as long asthe tracing and scribing arms. Because of this the apparatus has a l tol ratio, By changing the pivot pin for the primary arms and lengtheningor shortening the scribing arms I2 the ratio of the apparatus may bechanged.

The invention is not to be understood as restricted to the details setforth since these may be modied within the scope of the appended claimswithout departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire tosecure by Letters Patent is:

1. An apparatus adapted to reproduce contours of templates andcomprising a base having an upstanding pivot pin thereon, a pair ofhorizontally disposed centrally crossed rotatable truss-type primaryarms each embodying a hubforming sleeve mounted rotatably about the pin,a pair of short horizontal members connected to, and extending radiallyin opposite directions from, the sleeve, and a pair of horizontallyextending opposed centrally bowed members having the central portionsthereof xedly connected to the outer ends of the short membersrespectively and their ends connected together, a pair of tracing armsextending betweenv the ends of the primary arms that are at one side ofthe base and having the outer ends thereof pivotally connected to suchends of the primary arms and their inner ends pivotally connectedtogether and provided with means for supporting a tracing tool, and apair of scribing arms extending between the other ends of the primaryarms and side of the base and having the outer ends thereof pivotallyconnected to such ends of the primary arms and their inner endspivotally connected together and provided with means for supporting atracing tool, and a pair of scribing arms extending between the otherends of the primary arms and having their outer ends pivotally connectedto said other ends of the primary arms and their inner ends pivotallyconnected together and provided with means for retaining a scribingtool.

3.An apparatus adapted to reproduce contours of templates and comprisinga base with an upstanding pivot pin thereon, a pair of comparativelylong, horizontally disposed, rotatable, centrally crossed, truss-typeprimary arms each consisting of a verticalLv extending hub-formingsleeve mounted rotatably about thepin, a

' pair of short horizontally extending members conhaving their outerends pivotally connected to said other ends of the primary arms andtheir inner ends pivotally connected together and provided with meansfor retaining a scribing tool.

2. An apparatus adapted to reproduce contours of templates andcomprising a base having an upstanding pivot pin thereon, a pair ofhorizontally disposed centrally crossed, rotatable, truss-type primaryarms each embodying a vertically extending hub-forming sleeve mountedrotatably about the pin, a pair of short horizontally extending tubeswelded to, and extending radially in opposite directions from, thesleeve, and a pair of comparatively long horizontally extending opposedcentrally bowed tubes having the central parts thereof welded to theouter ends of the short tubes and their ends welded together, a pair oftracing arms extending between the ends of the primary arms that are atone 1 5 nected to and extending radially in opposite directions from,the lower end of the sleeve. a pair of 'comparatively long horizontallyextending opposed centrally bowed members having the central partsthereof xedly connected to the outer ends of the short members and theirouter ends xedly secured together, and a pair of diagonal oppositelyextending brace forming members connected to, and projecting outwardlyin opposite directions from, the upper end of the sleeve and having theouter ends thereof connected to the ends of the centrally bowed members,a pair of short tracing arms extending between the ends of the primaryarms that are at one side of the base and having the outer ends thereofpivotally connected to such ends of the primary arms and their innerends pivotally connected together and provided with means for supportinga tracing tool, and a pair of short scribing arms extending between theother ends of the primary arms and having their outer ends pivotallyconnected to said other ends of the primary arms and their inner endspivotally connected together and provided with means for retaining ascribing tool.

4. An apparatus adapted to reproduce contours of templates andcomprising a base having an upstanding pivot pin, a pair of horizontallydisposed centrally crossed rotatable truss-type primary arms, one ofsaid arms consisting of a vertical hub forming sleeve mounted rotatablyon the pivot pin, a pair of horizontally extending opposed centrallybowed members having the central portions thereof xed to the lowerportion of the sleeve, and a pair of diagonal brace members connectedto, and extending in opposite directions from, the upper end of saidsleeve and having the outer .ends thereof connected to the ends of saidcentrally bowed members, the other primary arm being the same in designand construction as said one arm but having the sleeve thereof rotatably.mounted on the sleeve of said one arm and having its centrally bowedmembers and its diagonal brace members overlying and underlyingthecentrally bowed members and the diagonal brace members of said onearm respectively, a pair of tracing arms extending between the ends ofthe primary arms that are at one side of the base and having the outerends thereof pivotally connected to such ends of the primary arms andtheir inner ends pivotally connected together and provided with meansfor supporting a tracing tool, and a pair of scribing arms extendingbetween the other ends of the primary arms and having their outer endspivotally connected to said other ends of the primary arms and theirinner ends pivotally connected together and provided with means forretaining a scribing tool.

5. An apparatus adapted to reproduce the contour of a template andcomprising a pair of centrally crossed primary arms pivotally connectedtogether at the point of crossing, a pair of tracing arms extendingbetween` certain oi' the ends of the primary arms and having the outerends thereof pivotally connected to said certain ends and their innerends secured together by a pivotal connection, a holder forming a partof, and disposed centrally with respect to, the pivotal connection, atracing tool adapted to engage and be moved around the edge of thetemplate and having mounting means between it and the holder whereby itis laterally adjustable to and from the center point of said pivotalconnection, and a pair of scribing arms extending between the other endsof the primary arms and having the outer ends thereof pivotallyconnected to said other ends and their inner ends pivotally connectedtogether and provided with means for retaining .a scribing tool.

6. An apparatus adapted to reproduce the contour oi a template andcomprising a pair oi cen-` trally crossed primary arms pivotallyconnected together at the point of crossing, a pair of tracing armsextending between certain of the ends of the primary arms and having theouter ends thereof pivotally connected to said certain ends and theirinner ends secured together by a pivotal connection, a holder forming apart of, and disposed centrally with respect to, Athe pivotalconnection, a roller disposed outwardly oi', the

holder and adapted to engage and-` be moved around the edge of thetemplate, means between the roller and holder for supporting said rollerso that it is adjustable laterally to and from the center point of saidpivotal connection, and a pair of scribing arms extending between theother ends of the primary arms and having the outer ends thereofpivotally connected to said other ends and their inner ends pivotallyconnected together and provided with means for retaining a scribingtool.

7. An apparatus adapted to reproduce the contour of a template andcomprising a pair of centrally crossed primary arms pivotally connectedtogether at the point of crossing, a pair of tracing arms extendingbetween certain of the ends of the primary arms and having the outerends thereof pivotally connected to said certain ends and their innerends secured together by a pivotal connection, a holder forming a partof, and disposed centrally with respect to, said connection, a rolleradapted to engage and be moved around the edge of the template,supportingr

